Storage apparatus, data write-in method, and data read-out method

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(11)

EP 0 890 955 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	01.09.1999 Bulletin 1999/35

(43)	Date of publication A2:
	13.01.1999 Bulletin 1999/02

(21)	Application number: 98112506.5

(22)	Date of filing: 06.07.1998

(51)	International Patent Classification (IPC)⁶: G11C 16/06

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

07.07.1997 JP 181540/97

(71)	Applicant: SONY CORPORATION
	Tokyo (JP)

(72)	Inventors:
	Sassa, Akira Shinagawa-ku, Tokyo (JP) Suzuki, Yuichi Shinagawa-ku, Tokyo (JP)

(74)	Representative: Melzer, Wolfgang, Dipl.-Ing. et al
	Patentanwälte Mitscherlich & Partner, Sonnenstrasse 33 80331 München 80331 München (DE)

(54)	Storage apparatus, data write-in method, and data read-out method

(57) The present invention prevents a damage concentration caused by a data erase/write-in to a particular cell, so as to increase a service life of a flash memory (2, 22).
A CPU 17 determines whether a data which has been read out is a new one or a data having a reverse flag set (step S1 and S2). If the reverse flag is not set, a reverse flag is set (step S3), so as to reverse the bit of the data when writing the data into a flash memory (2, 22) (steps S4 and S6). If a reverse flag is set, the reverse flag is reset (step S5) and the data is written into the flash memory (2, 22) (step S6).

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